The present invention relates to a single-pole switching unit. It also relates to a switching unit comprising at least one single-pole switching unit.
It belongs to the field of switching units, in particular high-power, low-voltage circuit breakers, in which the discharge of the switching gases is used to trigger a current switching mechanism.
In such switching units, it is necessary to trigger the mechanism opening the circuit breaker once an arc appears in the cutoff chamber.
Various solutions have been proposed to achieve quick triggering.
Patent application FR2986659 describes a modular switching unit, comprising improved pneumatic triggering means.
This document describes a switching unit comprising at least one single-pole switching unit, and preferably three single-pole switching units, each single-pole switching unit being connected to a triggering unit at a downstream contact. Each single-pole switching unit also comprises an upstream contact, making it possible to connect it to a current line. Such a single-pole switching unit comprises a housing comprising a moving contact bridge and connected to the contact areas, as well as two electric arc cutoff chambers opening onto an open volume of the contact bridge, each cutoff chamber being connected to at least one switching gas exhaust channel. If an electric arc occurs, switching gases pass through the exhaust channels and cause triggering of the opening contacts to produce the electric cutoff.
Each single-pole switching unit comprises, for at least one exhaust channel, a rotating gate designed to be rotated by the passage of the cutoff gases around an axis of rotation substantially perpendicular to the exhaust channel, the rotation of the gate from a first obstructing position to a second triggering position being designed to actuate triggering means to cause the contacts to open. The axis of rotation of the rotating gate is fastened to the side walls of the discharge channel so as to divide the gate into two non-symmetrical working surfaces, a first and a second surface, which, moving from the first obstruction position to the second triggering position, free two passage sections for gases in the gas exhaust channel.
With this known rotating gate, solid debris builds up in the gas discharge channel, causing obstruction of the channel and preventing the operation of the device multiple times.